public function hasField($fieldName)
 {
     $nameSegments = CoreServices::get('request')->getFormFieldNameSegments($fieldName);
     if (sizeof($nameSegments) == 1) {
         return parent::hasField($fieldName);
     } elseif (sizeof($nameSegments) == 3) {
         return $this->vlfs[$nameSegments[0]]->hasActualField($nameSegments[1], $nameSegments[2]);
     }
     throw new CoreException('Invalid field name \'' . $fieldName . '\'.');
 }